As mechanical seal device is installed in apparatus for mass production or massive processing, such as automobiles or chemical apparatus, ease of installation and straightforwardness of assembly, disassembly and maintenance have been demanded in market. The mechanical seal device is requested to retain a construction for being able to reduce production cost thereof. Also as the mechanical seal device is used for sealing sealed fluid such as oils or chemical liquid, there have been demands for prevention of occurrence of operational troubles in sliding surfaces due to solidifications of the liquid as sealed fluid. In these years, the above technical background necessitates a simplification of the construction of the mechanical seal device, prevention of operational troubles of sliding surfaces and enhancement of durability of packing, O-ring and the like for sealing between part members.
Related prior art of the present invention is found as a mechanical seal device is shown in FIG. 4 which has a similar construction to the one disclosed in Patent Reference 1, given below. FIG. 4 illustrates a full cross section of a mechanical seal device 100 which is installed in a casing 160. The mechanical sea device 100 is utilized as a shafts seal apparatus of a pump which operates with chemical liquid and the like.
First, the construction of this mechanical seal device 100 will be explained briefly. In FIG. 4 the mechanical seal device 100 provides a seal between the casing 160 and a rotary shaft 150 which extends through within a bore diameter surface 160A (inboard “A”) of the casing 160. Also the mechanical seal device 100 is provided in a cartridge type so as to be mounted on the end surface 160B of the casing 160 for easy installation. The mechanical seal device 100 includes a stationary seal ring 102 and a rotary sea ring 112 which are disposed within the bore diameter surface 160A. In addition, primary constitution members include a casing main body 130 and a sleeve 125 in which the casing body 130 retains the stationary seal ring (axially displaceable seal ring) 102 and retainer 106 thereof in the outboard “B” in relation to the casing 160 and the sleeve 125 retains the rotary seal ring 112 within the bore diameter surface 160A with which the rotary shaft 150 fittingly mates with a clearance gap formed therebetween.
The rotary seal ring 112 is mounted on one end portion located at the inboard “A” side of a long sleeve 125 in order to be disposed in the inboard “A” in relation to the bone diameter surface 160A of the casing 160. The other end portion of the sleeve 125 at the outboard “B” side is securely attached to a retainer portion 127 while a screw socket 128 in the retainer portion 127 is fastened so as to fix the retainer portion 127 with the rotary shaft 150. And the coupling of the rotary seal ring 112 and the sleeve 125 is realized by means of a coupling element 126. Respective fit clearances between the rotary shaft 150 and sleeve 125 and between the sleeve 125 and coupling member 126 dispose O-rings for sealing the clearances. And the sleeve 125 and the coupling member 126 are coupled by means of a drive pin 129 so as to rotate together. Furthermore, the coupling member 126 and the rotary seal ring 112 are coupled in a jointly rotatable relation by means of the drive pins locking in the U-shaped grooves 112A. In addition, the fit clearance between the coupling member 126 and the rotary seal ring 112 is provided a seal by O-ring 141.
The stationary seal ring 102, on the other hand, is securely attached to the annular surface with a step shoulder which is disposed at one end portion of the cylindrical retainer body 106. The retainer body 106 is retained in a non-rotatable manner while being freely moveable in the axial direction by means of a locking engagement between a fixation pin 137 disposed in the casing main body 130 and a long groove 106C disposed in the retainer body 106. The fit clearance between the retainer body 106 and the casings main body 130 which are freely moveable relative to each other is provided a seal by means of an O-ring 143 which is mounted between a first steps shoulder surface 106A of the retainer body 106 and a second step shoulder surface 130A of the casing main body 130. And the other end portion of the retainer body 106 fittingly receives and fixates a spring receiving portion.
End portion 130F of the casing main body 130 forms a contact with an end surface 160B of the casing 160 while the casing main body 130 is fixed to the casing 160 by means of stud bolts 128B anchored to the casing 160 with nuts 128A fastened. There is disposed a double step shoulder surface on the frontal end surface (side surface) of the casing main body 130. A spring seat member 107 is installed in the first step shoulder surface by means of set screw portion. A spring supported by the spring seat member 107 is disposed between the spring seat member 107 and a spring receiving portion. The stationary seal ring 102 is resiliently urged by the spring 120 by way of the spring receiving portion and the retainer body 106. The seal surface 102F of the stationary seal surface 102 urged by the spring 120 forms a seal-tight contact with the seal surface 112F of the rotary seal ring 112 for sealing a sealed fluid. There is disposed amount groove in the inner circumference of the spring seat member 107. This mount groove receives a spirally wound gasket 146 therein. The seal surface of this gasket 146 is in a seal-tight contact with the outer circumferential surface of the sleeve 126.
In order to cool the seal surfaces of the rotary seal ring 112 and the stationary seal ring 102, a flushing passage 136 and a quenching passage 135 extend in a communicating manner from the outer circumferential surface of the casing main body 130 to inner circumferential surface thereof in which the flushing passage 136 passes outer circumferential side of the rotary seal ring 112 and the stationary seal ring 102 while the quenching passage 135 passes inner circumferential surfaces of the rotary seal rings 112 and the stationary seal ring 102. Then the flushing passage 136 permits flushing fluid while the quenching passage 135 permits quenching fluid.
A mechanical seal device 100 thus configured which is required to dispose the rotary seal ring 112 in the inboard “A” side in relation to the bore diameter surface 160A of the casing 160 necessitates a long sleeve 125 in order to fix the rotary seal ring 112 thereon. It also requires disposition of a flushing passage 136 and a quenching passage 135 in the case main body 130 for cleaning the outer circumferential surface of the rotary seal ring 112 and the stationary seal ring 102 by means of flushing fluid. It also needs to provide a cooling to the mechanical seal by supplying quenching fluid to the inner circumferential side of the rotary seal ring 112 and the stationary seal ring 102 which comprise the mechanical seal. A retainer body 106 also needs to be disposed in the stationary seal ring 102. A coupling member 126, at the same time, is necessarily disposed in the rotary seal ring 112. Therefore, the sleeve 125 necessarily becomes long toward inboard “A” side in relation to the bore diameter surface 160A of the casing 160. As the result, the flushing fluid which passes through the narrow passage formed at the outer circumferential surface side of the rotary seal ring 112 and the stationary seal ring 102 suffers from insufficient cleaning effect on the rotary seal ring 112 and the stationary seal ring 102. Likewise, the quenching fluid which passes through the narrow passage formed at the inner circumferential surface side of the rotary seal ring 112 and the stationary seal ring 102 suffers from insufficient quenching fluid flow and insufficient cooling effect on the rotary seal ring 112 and the stationary seal ring 102.
The bore diameter surface 160A typically cannot be chosen so large due to a structural constraint as a casing of machinery or apparatus. As the bore diameter surface 160A of the casing 160 often cannot be made large from the structural viewpoint. The rotary seal ring 112 and the stationary seal ring 102 necessarily become large in order to improve seal ability thereof, which in turn forces the space “S” in the inner circumference of the rotary seal ring 112 and the stationary seal ring 102 as well as the space between the bore diameter surface 160A and the outer circumferential surface of the rotary seal ring 112 and the stationary seal ring 102 to be arranged narrow and long. As the result, the foresaid cooling effect and cleaning effect become even worse. There is a possible threat that adhesive matters such as impurities produced from the sealed fluid may get caught between the seal surfaces 102F, 112F and on the seal surface of the O-ring 143 between the first step shoulder surface 106A and the second step shoulder surface 130A and may deteriorate seal performances of the seal surfaces 102F, 112F in a seal tight contact relation to each other and of the seal surface of the O-ring 143.
In particular, if reaction product of chemical liquid, slurry, high viscosity liquid and the like get caught between the O-ring 143 and the first step shoulder surface 106A or the second, step shoulder surface 130A, the adhesive matters make the O-ring 143 get stuck and accumulation of such adhesive matters makes displacement of the retainer body 106 difficult. If the displacement of the retainer body 106 becomes difficult, then the seal performance of the seal surfaces 102F, 112F in a contact relation to each other will decrease. Furthermore, the respective O-rings disposed more inward of the inboard “A” than the rotary seal ring 112 and the stationary seal ring 102 provide a seal to prevent the fluid from the quenching passage 135 from breaking into the inboard “A” and also provide a seal to prevent the sealed fluid within the bore diameter surface 160A from breaking into the quenching passage 135, hence complex construction for installing the respective O-rings. In particular, as some type of devices prohibit bore diameter surface 160A of the casing 110 in large diameter, the rotary seal ring 112 and the stationary seal ring 102 cannot be formed in larger dimensions in these cases. Thus, these cases fail to enhance the performance of the mechanical seal device 100.
Patent reference 1: Japanese Unexamined Patent Application Publication No. 2000-356270